body{
    background: url("../../public/photo/bg.jpg") no-repeat;
    background-size: 100%;
}
.main{
    width: 600px;
    height: 300px;
    margin: 200px  auto;
    background: url("../../public/photo/log.jpg") no-repeat;
    background-size: 600px 300px;

}
.form{
    width:40%;
    float: left;
    height: 100%;
    line-height: 60px;
    text-align: center;
    font-size: 20px;
}